Implement WEBGL_shared_resources

Source/core/html/canvas/WebGLContextObject.h

 /*
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 24 matching lines @@
 class WebGLRenderingContext;
 
 // WebGLContextObject the base class for objects that are owned by a specific
 // WebGLRenderingContext.
 class WebGLContextObject : public WebGLObject {
 public:
     virtual ~WebGLContextObject();
 
     WebGLRenderingContext* context() const { return m_context; }
 
-    virtual bool validate(const WebGLContextGroup*, const WebGLRenderingContext* context) const
+    bool validate(const WebGLContextGroup*, const WebGLRenderingContext* context) const
     {
         return context == m_context;
     }
 
     void detachContext();
 
 protected:
     WebGLContextObject(WebGLRenderingContext*);
 
     virtual bool hasGroupOrContext() const
     {
         return m_context;
     }
 
     virtual GraphicsContext3D* getAGraphicsContext3D() const;
 
 private:
     WebGLRenderingContext* m_context;
 };
 
 } // namespace WebCore
 
 #endif // WebGLContextObject_h